Forest UCM MnAM InElasticCol

An Inelastic collision conservers Momentum But Not energy

Consider a collision between two bodies of mass $m_1$ and $m_2$ initially moving at speeds $v_1$ and $v_2$ respectively. They stick together after they collide so that each is moving at the same velocity $v$ after the collision.

If there are no external force then

Conservation of momentum

$m_1 v_1 + m_2 v_2 = \left (m_1 + m_2 \right ) v$

Given that the amsses and initially velocities are known we can solve for v such that

$v= \frac{m_1 v_1 + m_2 v_2}{m_1 + m_2}$

Forest_UCM_MnAM#Inelastic_Collision_of_2_bodies

problem 3.4 two hobos

Two hobos are standing at one end of a stationary railroad flatcar of mass $M$. Each hobo has a mass $m$ and the flatcar has frictionless wheels. A hobo can run to the other end of the car and jump off with a speed $u$ with respect to the car.

a.) Find the final speed of the car if both men run and jump off simultaneously.